Barrier Layer Removal Method and Apparatus

Abstract

A method and apparatus integrating semiconductor manufacturing processes of stress free electrochemical copper polishing (SFP), removal of the Tantalum oxide or Titanium oxide formed during SFP process and XeF 2 gas phase etching barrier layer Ta/TaN or Ti/TiN process. Firstly, at least a portion of the plated copper film is polished by SFP. Secondly the barrier metal oxide film formed during SFP process is etched away by etchant. Finally, the barrier layer Ta/TaN or Ta/TiN is removed with XeF 2 gas phase etching. The apparatus accordingly consists of three sub systems: stress free copper electropolishing system, barrier layer oxide film removal system and barrier layer Ta/TaN or Ti/TiN gas phase etching system.

What is claimed is: 
     
         1 . An apparatus for processing a semiconductor structure, which comprises a substrate, a dielectric layer, a barrier layer on the dielectric layer, and a metal layer on the barrier layer, the structure has patterns and the metal layer fills the patterns, wherein the apparatus comprises:
 a stress-free electropolishing system for removing the metal layer above the barrier layer by stress-free electropolishing (SFP);   a Tantalum oxide or Titanium oxide film removing system for removing the Tantalum oxide or Titanium oxide film of the barrier layer formed during the stress-free electro-polishing, wherein the Tantalum oxide or Titanium oxide film removing system uses etching reagent to remove the Tantalum oxide or Titanium oxide film, the etching reagent is a solution contains HF/BHF;   an etching system for removing the barrier layer to completely separate the patterns in the structure by using XeF 2  gas.   
     
     
         2 . The apparatus of  claim 1 , wherein the barrier layer is selected from the group consisting of Ta, Ti as pure elements, compounds or with additions of nitrogen or silicon. 
     
     
         3 . The apparatus of  claim 1 , wherein the concentration of the etching reagent varies from 0.1% to 30%, and
 the temperature is from 0° C. to 50° C., and   the etching reagent also contains F −  with addition of HCl or H 2 SO 4 .   
     
     
         4 . The apparatus of  claim 1 , wherein the pressure of the XeF 2  gas is between 0.1 Torr and 100 Torr. 
     
     
         5 . The apparatus of  claim 4 , wherein the temperature of the substrate is from 0° C. to 300° C. 
     
     
         6 . An apparatus for processing a semiconductor structure, which comprises a substrate, a dielectric layer, a barrier layer on the dielectric layer, and a metal layer on the barrier layer, the structure has patterns and the metal layer fills the patterns, wherein the apparatus comprises:
 a stress-free electropolishing system for removing the metal layer above the barrier layer by stress-free electropolishing (SFP);   a Tantalum oxide or Titanium oxide film removing system for removing the Tantalum oxide or Titanium oxide film of the barrier layer formed during the stress-free electro-polishing, wherein the Tantalum oxide or Titanium oxide film removing system uses etching reagent to remove the Tantalum oxide or Titanium oxide film, the etching reagent is a strong base solution containing KOH or NaOH or both;   an etching system for removing the barrier layer to completely separate the patterns in the structure by using XeF 2  gas.   
     
     
         7 . The apparatus of  claim 6 , wherein the concentration of the solution varies from 0.1% to 50%, and the temperature is from 0° C. to 90° C. 
     
     
         8 . An apparatus for processing a semiconductor structure, which comprises a substrate, a dielectric layer, a barrier layer on the dielectric layer, and a metal layer on the barrier layer, the structure has patterns and the metal layer fills the patterns, wherein the apparatus comprises:
 a stress-free electropolishing system for removing the metal layer above the barrier layer by stress-free electropolishing (SFP);   a Tantalum oxide or Titanium oxide film removing system for removing the Tantalum oxide or Titanium oxide film of the barrier layer formed during the stress-free electro-polishing, wherein the Tantalum oxide or Titanium oxide film removing system uses etching reagent to remove the Tantalum oxide or Titanium oxide film, the etching reagent is citric acid or oxalic acid or a mixture of the two;   an etching system for removing the barrier layer to completely separate the patterns in the structure by using XeF 2  gas.   
     
     
         9 . The apparatus of  claim 8 , wherein the concentration of the reagent varies from 0.1% to 10%, and the temperature is from 0° C. to 80° C.